Is it weird to break up with GF because of her best friend

So me (23M) and GF (20F) already have a lot of problems in the relationship we need to address. Just to name two, we have a libido mismatch and we don't really open up to each other emotionally. They are not relationship-breaking to me because I believe it's possible to find solutions for the problem and we can live as a happy couple after.

But here's the thing, she has a best friend that hates me for whatever reason.

1. My girlfriend says she talks shit about me to her (which GF says she defends me when she does), but why would she allow her to do that? If someone talks shit to me about my girlfriend, I won't sit there passively defending her, I'll be furious at them and tell them to cut it out or cut them out of my life. My GF is not doing that, she let the friend continue to do it.
2. I can't stand interacting with the friend. I get along with every other friend of GF's and her family. But her best friend has a really smug attitude towards me and I can tell she hates my guts. I don't know how to explain it. Like she'd say things to put me down and correct me on things whenever she has a chance. I tell my girlfriend about this and she brushes me every time basically just saying I imagined these things and her best friend is just the way her best friend is. Which I'm really mad/disappointed/heart broken about because it feels like GF doesn't have my back and sides with her friend.
3. GF and the friend is really close to each other and are basically sisters, so if I keep dating GF, she will forever be a part of my life and I don't look forward to that at all.

Given the problems we already have and the friend, would it be fair to call it quits now? Or should I suck it up? I feel like it isn't for me anymore but I feel weird because this basically boiled down to the issue with the friend, if she wasn't there I would have kept working on our other issues.

TL;DR: Already have problems in our relationship. The problems are workable, but I don't want to work on them anymore because GF has a best friend that's basically her sister who I really don't want to be a part of my life forever. Is it fair to break up now or should I suck it up?

Submitted August 26, 2021 at 03:17PM by momomomofo https://ift.tt/3sR33xz